Class 12 Physics, Chapter 7 Alternating current Class 12 Physics, Chapter 7 Alternating current | Page 13

minimum and currents has its maximum value
Hence at resonance ωL = 1 / ωC or ω = 1 / √LC --- ( 21 ) But ω = 2πf where f is the frequency of applied voltage . Therefore f 0 = 1 / 2π√LC --- ( 22 ) This frequency is called resonant frequency of the circuit and peak current in this case is i 0 = V 0 / R and reactance is zero
We will now define resonance curves which shows the variation in circuit current ( peak current i 0 ) with change in frequency of the applied voltage
Figure below shows the shape of resonance curve for various values of resistance R
For small value of R , the resonance is sharp which means that if applied frequency is lesser to resonant frequency f 0 , the current is high otherwise
For large values of R , the curve is broad sided which means that those is limited change in current for resonance and non -resonance conditions